New York City's mayor has paid a call on Pope Francis' top aide to discuss migration issues.

During his holiday in Rome, Mayor Bill de Blasio met Monday with Cardinal Pietro Parolin, the Vatican secretary of state.

Vatican spokesman the Rev. Federico Lombardi said the two explored approaches to migration.

Parolin recently returned from a meeting in Mexico dedicated to migration issues and human rights.

Pope Francis has called for "urgent intervention" to protect migrant minors crossing into the United States on their own. Earlier this month, De Blasio signed a measure offering ID cards to city residents regardless of immigration status.

Lombardi said the chat also provided an "obvious" opportunity for the mayor to offer a welcome mat, should Francis visit the United States next year as many expect.

New York City's mayor has paid a call on Pope Francis' top aide to discuss migration issues.During his holiday in Rome, Mayor Bill de Blasio met Monday with Cardinal Pietro Parolin, the Vatican secretary of state.Vatican spokesman the Rev. Federico Lombardi said the two...